Why is the automatic backwash filter for the feed oil in the hydrogenation unit experiencing high pressure differences and frequent backwashing?
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Dear everyone, the automatic backwash filter for the crude oil is flushing frequently, and the reason given is an excessive pressure difference. So what could be the issue on the instrumentation side that causes such frequent backwashing, and how can it be resolved?
Is it due to the raw materials or the instruments?
Reply to 2# Zhang Yanchun: I just want to know what could be the cause if it’s related to the instrument
You can compare it with the pressure gauge on site and contact the instrument manufacturer for calibration; generally, it is due to poor oil quality – in such cases, the oil in question can be returned to the tank area to be replaced for a while before taking samples for further inspection. The sampling is clean, and backwashing can be performed manually with very noticeable results
Reply to 4# HCLY: Do you mean to calibrate the differential pressure transmitter connected to the PLC? Is it suspected that the transmitter is faulty? For example, is the range incorrect?
Instrument-related cause: Faulty differential pressure measurement leads to frequent flushing, or a low set value for the differential pressure also results in frequent flushing. Adjust the instrument to ensure accurate differential pressure measurement, or increase the set value appropriately to reduce the frequency of flushing
Check if it’s a problem with the raw materials; if there are many impurities in them, the differential pressure will be high. If that’s not the case, then check whether it’s an issue with the instruments
My suggestion is that you first compare the differential pressure shown on the indoor DCS with that indicated by the pressure gauge on site, to verify whether the values match； If the readings are consistent, then it is your unit that is dirtier. If it is dirtier, the differential pressure increases more rapidly, and therefore the flushing cycle will need to be carried out more frequently according to the originally set time. Since this original time was determined by the manufacturer of the backwashing system, a short flushing time makes it difficult to achieve an effective cleaning effect. It is recommended that you contact the instrument manufacturer to increase the flushing time; this way, the impurities in the filtration tank can be cleaned properly, and the flushing time can be extended.
Another possibility is that some filter elements are clogged or a certain group of switch valves has not been in use for an extended period of time. You can judge by feeling the temperature
Compare it with the differential pressure gauge on site; generally, frequent backwashing of the automatic backwash filter is caused by overly dirty oil.
Reply to 1# Deep Blue Rain: What is your raw material? If it’s a problem with the instruments, have the instrument specialists handle the repair; if it’s a problem with the raw material, bypass the filter first and contact the irrigation department to deal with it, then resume operation once everything is fixed